Pulmonary edema

Definition: What is pulmonary edema?

Pulmonary edema is an accumulation of fluid (edema) in the lung tissue that leads to a gradual reduction of gas exchange in the lungs as the volume increases.

There are two stages or types of pulmonary edema, depending on the location of the fluid:

• Interstitial pulmonary edema: initially, the fluid is located exclusively in the pulmonary interstitium (connective tissue of the lungs) and leads to a constriction of the airways.

• Pulmonary alveolar edema: the lung tissue has a relatively low ability to absorb fluid and remove it via the lymphatic system. This results in the fluid passing rapidly from the interstitium into the pulmonary alveoli. This marks the transition from interstitial to alveolar pulmonary edema.

Cause: How does pulmonary edema occur?

Pulmonary edema can be divided into cardiogenic (affecting the heart) and noncardiogenic pulmonary edema, depending on the cause.

Cardiogenic pulmonary edema:

Cardiogenic pulmonary edema arises because of heart disease involving a reduced pumping capacity of the left heart. The reduced cardiac output of the left ventricle causes the blood to back up into the pulmonary veins, leading to an increase in blood pressure in the pulmonary capillaries (the smallest blood vessels in the lungs).

This rise in pulmonary capillary pressure causes fluid to leak from the pulmonary capillaries into the pulmonary interstitium and later into the alveoli, resulting in pulmonary edema. If the fluid penetrates the alveoli, their function of gas exchange, including oxygen uptake, is significantly impaired.

Cardiogenic pulmonary edema can occur in the following heart diseases:

• Acute or chronic left heart failure (cardiac insufficiency of the left ventricle)

• Aortic valve stenosis, mitral valve stenosis (narrowing of the aortic or mitral valve)

• Tachycardic cardiac arrhythmias (cardiac arrhythmias with a heart rate of > 100 beats/min)

• Hypertensive heart disease (heart disease due to high blood pressure)

Noncardiogenic pulmonary edema:

Pulmonary edema can also occur without the presence of heart disease; this is known as noncardiogenic pulmonary edema. Potential causes for this include:

• Increased permeability of the pulmonary capillary walls due to:
  • Toxins: e.g. chlorine gas, flue gas, etc.
  • Medication: e.g. azathioprine, bleomycin
  • Infections: viruses, mycoplasma (genus of bacteria)
  • Aspiration (inhalation of liquids or solids): e.g. gastric juice, fresh water, salt water
• Protein deficiency (decrease in oncotic pressure): renal insufficiency

• Oxygen deficiency (due to hypoxia): as part of altitude sickness (also known as high-altitude pulmonary oedema)

Symptoms: How does a pulmonary edema present itself?

The symptoms of pulmonary edema differ depending on the severity of the edema.

The typical symptoms are:

• Shortness of breath (dyspnea)

• Increased breathing frequency (tachypnea)

• (Nocturnal) coughing attacks with shortness of breath (cardiac asthma)

• Foamy, sometimes bloody sputum

• Rales in breathing with alveolar pulmonary edema

• Accelerated heartbeat (tachycardia)

• Pallor

• Bluish-reddish discoloration of skin and mucous membranes due to lack of oxygen (cyanosis)

• Restlessness up to and including fear of death/suffocation

Diagnosis: how does a doctor diagnose pulmonary edema?

The first step is to take a detailed medical history, in which the patient's symptoms and pre-existing conditions, such as heart or lung disease, are discussed.

A physical examination is then carried out. This involves listening to the lungs with a stethoscope. In the case of pulmonary alveolar edema, typical rales are detected, which in severe cases can even be heard without a stethoscope. With interstitial pulmonary edema, the examination will only reveal non-characteristic findings, such as a more pronounced breathing noise or wheezing.

Other symptoms that may indicate the presence of pulmonary edema in the clinical examination are an accelerated heart rate (> 100 beats/min), an accelerated respiratory rate and a blue discoloration of the skin and mucous membranes (e.g. lips).

An X-ray of the chest is then taken to visualize the lungs and heart (chest X-ray). Typical radiological signs of pulmonary edema can be detected in this, and the diagnosis confirmed.

Additional tests are carried out to determine the cause of the pulmonary edema. These include:

• ECG (electrocardiography)

• Echocardiography: ultrasound examination of the heart

• Ultrasound examination of the pericardium, the inferior vena cava and the abdominal organs

• MRI examination of the heart (cardiac MRI)

• Laboratory analysis from a blood sample

• Cardiac catheterization

• Stress tests (e.g. stress ECG, stress echocardiography)

Prognosis and chances of recovery: how dangerous is pulmonary edema?

A severe, acute pulmonary edema is a dangerous condition that is potentially life-threatening and can be fatal without treatment. However, if treatment is administered immediately, the prognosis is generally good.

A longer stay in hospital is usually necessary to treat pulmonary edema in all cases. The exact treatment procedure, however, depends primarily on the underlying disease.

If the pulmonary edema was caused by heart failure, the patient will need to be readmitted to the hospital within the next 12 weeks in one-fifth of cases. Therefore, successful treatment of pulmonary edema usually requires long-term management. Additionally, lifestyle changes are essential to prevent further heart disease and to avoid the worsening of existing heart conditions.

Which doctors and clinics are specialists in pulmonary edema?

If difficulties in breathing like shortness of breath or coughing develop gradually, then your general practitioner, cardiologist (heart specialist) or pulmonologist (lung specialist) are the right people to contact.

In the case of acute, severe shortness of breath, emergency medical treatment by the ambulance service or in hospital is necessary. Treatment is then usually provided by specialists in the field of pneumology (lung specialists).

Anyone in need of a doctor would expect the best possible medical care for themselves. Therefore, patients are looking for the most suitable clinic for their needs. Since this is not an objective decision and a respectable doctor would refrain from claiming to be the best, patients must trust the experience of a doctor.

We can help you find an appropriate expert for your condition. All the doctors and clinics listed have undergone extensive review and have been verified by us for their outstanding expertise in the field of pulmonary edema. They are looking forward to and are ready to address your questions and treatment requests.